A typical semiconductor wafer with a containing die and having a flat edge is illustrated in FIG. 1. A process using a wafer map eliminates the inking of reject die at a wafer fab by using the map data available from the probe test to position the wafer to exact location of all the good die on the Die Bonder or Tape and Reel. Hence, direct jumps to good die are possible without scanning the whole wafer. The wafer map coordinates are illustrated in FIG. 2.
In wafer mapping, the wafer map data contains good, bad, plug and edge dies coordinates with reference to a reference die of a wafer. A bin number in wafer map data is a category of dies. For example, bin 1 is all good first grade dies, bin 2 is all good second grade dies, bin 3 is all plug dies, bin 4 is all bad edge dies and bin 5 is edge bad dies.
For wafer map operation, each piece of wafer requires a reference die to process that wafer. A full wafer has one reference die. Wafers are also processed in halves, quarters, and other sizes to match production lot size at an Assembly/Test (A/T) site. In case of partial wafers, reference die in each piece of wafer is not available.
Without a method to process partial wafers using wafer map, small die wafer map operation is incomplete and cannot be fully implemented in assembly operations. Alternatives like scrapping partial wafers or processing all dies on partial wafers are not cost effective solutions.
Partial wafer processing is described in Balamurugan et al. patent application Ser. No. 09/188,989 filed Nov. 9, 1998 entitled “Partial Semiconductor Wafer Processing; Balamurugan patent application Ser. No. 09/262,265; filed Mar. 4, 1999 and entitled “Partial Semiconductor Wafer Processing with Multiple Cuts of Random Sizes”; and Balamurugan application Ser. No. 09/262,554 filed Mar. 4, 1999, entitled “Partial Semiconductor Wafer Processing Using Wafermap Display.” These applications are incorporated herein by reference. While the method of partial wafer processing Ser. No. 09/262,265 permits processing with random cuts others than quartered and half, the method is not easily suitable for processing outside the local fab and the last column of the first row must contain a die. This system requires a locator die coordinate and uses the wafer map host to store and manipulate the data.
It is desirable to provide new methods that provide a way to process partial wafers in different sizes other than quarter or half to match production requirements or production lot size and at different locations. It is desirable that these partial wafers be easily processed at different fabs from that where the wafer map was generated. These fabs may be within the same company or outside the company. A better method is desirable for processing partial wafers even if the last column of the first row does not contain a die and without both x and y coordinate information and without a reference die.